Why oranges spark when you hold a flame to them

Everyone knows oranges are sweet and sticky, but did you know they are also flammable? Bartenders will often perform a simple trick with an orange rind and a flame to both add flavor to a drink and wow customers. A little squeeze of the fruit's peel can actually create quite a spark if done correctly. Here's a quick look at why orange rinds are so combustible — and how you can pull off this trick yourself.